State-shift priority based progressive load control of residential HVAC units for frequency regulation

Abstract

The high penetration combined with the intermittent nature of large-scale distributed generation challenges the stability of power systems. Recently, it has been proposed that thermostatically controlled loads, such as heating, ventilation and air conditioner (HVAC) loads, can be controlled to provide efficient and effective frequency regulation (FR) service with a minimum impact on consumers’ comfort compared to the costly conventional spinning reserve. This paper proposes a progressive load control strategy which enables residential HVAC loads to implement primary and secondary frequency regulation. In particular, a state-shift priority approach is proposed to efficiently choose responsive loads and avoid frequent activations of load control. A state-shift time based random recovery approach is developed to mitigate load rebound after the control period. With the proposed load control strategy, the aggregation of HVAC units can behave like a synchronous generator to provide FR service. As a result, the required spinning reserve can be reduced. The dynamic simulation results indicate that HVAC units can provide a reliable and smooth FR service quickly via the proposed progressive load control strategy based on state-shift priority.